The invention relates generally to gas turbines and, more particularly, to a fuel nozzle for a gas turbine engine including a cooling circuit that utilizes passive purge flow for fuel nozzle tips supplied from end cap cooling flow before quat fuel injection.
Conventional quat fuel injection systems utilize CdC air mixed with quat fuel for passive purge feeds. The presence of fuel in the passive purge feed elevates a risk of flame holding in the passive purge cavities and within the fuel nozzle tips. It would be desirable to use the end cap purge feed that is free of quat fuel to provide an alternate means to purge the fuel nozzle tips and eliminate the flame holding risk from the design.